Andrew Luck and the Indianapolis Colts got shellshocked in Sunday’s stunning 38-8 home loss to St. Louis. While Luck had his worst game of the season (353 yards, TD, 3 INTs, 3 sacks, lost fumble) against the Rams’ defense, it was another reminder that they are getting no happy returns from the trade for Trent Richardson.

The running back whom the team acquired in September to strengthen its identity as a physical, power rushing offense to take pressure off Luck hasn’t really done that. Richardson got only 5 carries for 2 yards as the Colts played catchup for most of the game, piling on to the fact he’s been a huge bust in Indianapolis.

Since he’s been a Colt, Richardson now has 88 carries for 250 yards over seven games—a paltry 35 yards per game at 2.8 yards per carry. Week 10 against a sputtering Rams run defense entering the week ranked 28th in run defense seemed like the best opportunity to get him going.

His struggles against the Rams started right away. He was stuffed on the first drive, putting Luck in an unfavorable third down situation. It led to a sack and fumble return for a touchdown by the Rams. Two more stuffs on the second possession, and that was pretty much Richardson’s day.

The Colts sent a first-round pick to the Browns to get Richardson. He looked like the perfect complement to big-armed Luck. Instead, with his limited production, Luck is back in the situation of having to chuck it (47 pass attempts) while teams such as the Rams tee off on him, knowing Indianapolis remains a one-dimensional team. He is on pace to be sacked 39 times and going into Sunday's game, he'd taken a whopping 63 hits—ahead of only Cleveland and Buffalo, who've played multiple quarterbacks all year.

If the Colts have buyer's remorse, it wouldn't be surprising. Losing Vick Ballard and Ahmad Bradshaw for the season, they needed Richardson to deliver. Yet, their most productive back remains Donald Brown. The biggest concern with Richardson was not anything regarding talent, but more his durability. He was able to play Sunday, but did so after battling an ankle injury all week.

Going into Sunday, a case could have been made the Colts were a strong AFC title contender, and given their wins over Denver, Seattle and San Francisco, they have built enough equity to keep thinking that way, despite the debacle vs. St. Louis.

But the Colts won’t be winning anything beyond a weak AFC South if they can’t get better contributions from Richardson running and receiving.